Prior to the present invention, there have existed a number of unsolved problems in so far as dentist's use of conventionally available instrument mounts for mechanized dental instruments such as drills, air blowing instrument, water mouth-rinsing instrument, water-suction instrument, and the like, basically the probelm being one of hinderances to the undivided attention of the dentist to his work and one of unrestricted movement manually, together with advantageous automatic withdrawal of the connector tube or line efficiently. At the same time, the simplicity of operation and construction of the equipment has a direct bearing on the continued long term durability of the equipment in a fully efficient operational state, and also has an effect on the question of maintenance and the cost thereof. Also, not all dentists are of the same height, nor are the patients, and often dentists find it desirable to sit, while other dentists still normally prefer to stand during the caring for a dental patient; these and other variables add to the complexities and problems associated with any effort to design any dental equipment equally satisfactory for any one or more of such variables.